vi - branches

lib/reverse_sentence.rb

@@ -1,6 +1,27 @@
 # A method to reverse the words in a sentence, in place.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n)
+# Space complexity: O(n)
+# Not pleased with how regex captures the whitespaces and think that it creates unneccesary iteration for the program to run. I couldn't figure a better one out though.
+
 def reverse_sentence(my_sentence)
-  raise NotImplementedError
+  if my_sentence == nil 
+    return nil 
+  end 
+
+  my_sentence_array = my_sentence.split(/(\S+|\s{1,})/)
+  length = my_sentence_array.length
+  index = 0 
+  temp = 0
+
+  while index < length / 2
+    temp = my_sentence_array[index] 
+    my_sentence_array[index] = my_sentence_array[length - index - 1]
+    my_sentence_array[length - index - 1] = temp 
+    index += 1
+  end 
+
+  reversed_sentence = my_sentence_array.join('')
+  my_sentence[0..my_sentence.length] = reversed_sentence
+
 end
+

lib/sort_by_length.rb

@@ -1,7 +1,20 @@
-# A method which will return an array of the words in the string
-#  sorted by the length of the word.
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(n^2)
+# Space complexity: O(n)
 def sort_by_length(my_sentence)
-  raise NotImplementedError, "Method not implemented"
-end
+  my_sentence_array = my_sentence.split(' ')
+  length = my_sentence_array.length
+  i = 1 
+
+  while i < length 
+    to_insert = my_sentence_array[i]
+    j = i 
+
+    while j > 0 && my_sentence_array[j-1].length > to_insert.length
+      my_sentence_array[j] = my_sentence_array[j - 1]
+      j -= 1
+    end 
+    my_sentence_array[j] = to_insert
+    i += 1
+  end 
+  return my_sentence_array
+end